If a baby continued to grow at the same rate as in the first 3 months of life, what would the child weigh at age 12 years?

The weight of a baby measured over an 11-month period is given in the weight chart below for this problem.
Weight (lb) Age (months)
6.6 0 (birth)
7.4 1.0
9.6 2.0
11.2 3.0
12.0 4.0
13.6 5.0
13.8 6.0
14.8 7.0
15.0 8.0
16.6 9.0
17.5 10.0
18.4 11.0

(a) What was the average monthly weight gain for this baby over the period from birth to 3 months?
1.53 lb/month

(b) What was the average monthly weight gain for the baby over the period from 8 months to 11 months?
1.13 lb/month

(c) If a baby continued to grow at the same rate as in the first 3 months of life, what would the child weigh at age 12 years?
????????????????????? lb